IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

Low Memory Maps (O-'0600'x)
Table 30. Interrupt Vectors (O-7F)
ADDRESS INTERRUPT
HEX HEX FUNCTION
0-3 0 Divide by Zero
4-7 1 Single step
8-B 2 Non-Maskable Interrupt (NMI)
C-F 3 Break Point Instruction ('CC'x)
10-13 4 Overflow
14-17 5 Print Screen
18-1 F 6,7 Reserved
20-23 8 Timer (18.2 per second)
24-27 9 Keyboard Interrupt
28-37 A,B,C,D Reserved
38-3B E Diskette Interrupt
3C-3F F Reserved
40-43 10 Video I/O Call
44-47 11 Equipment Check Call
48-4B 12 Memory Check Call
4C-4F 13 Diskette I/O Call
50-53 14 RS232 I/O Call
54-57 15 Cassette I/O Call
58-5B 16 Keyboard I/O Call
5C-5F 17 Printer I/O Call
60-63 18 ROM Basic Entry Code
64-67 19 Boot Strap Loader
68-6B 1A Time of Day Call
6C-6F 1B Get Control on Keyboard Break: Note 1
70-73 1C Get Control on timer interrupt: Note 1
74-77 10 Pointer to video initialization table: Note 2
78-7B 1E Pointer to diskette parameter table: Note 2
7C-7F 1F Pointer to table (1 KB) for graphics character
Generator for ASCII 128-255. Defaults to 0:0
Notes:
(1 ) Initialized at power up to point to an IRET Instruction.
(2) Initialized at power up to point to tables in ROM.
3-21